Step by step: Tweaking your router's settings
It's not at all unusual for a router manufacturer to release new firmware updates over the router's useful life. These updates typically include rudimentary bug fixes and performance enhancements, but they sometimes include entirely new functions that didn't exist when the router was first shipped. Either way, it's always a good idea to make sure you have the latest version.
Before configuring your router's QoS settings, check the support pages on the manufacturer's Web site to see if any new firmware is available. If there is a new version, follow the instructions you'll find there to download and install it.
I'm using D-Link's Xtreme-N DIR-655 wireless router as an example in this story, simply because it's a very popular model that's still available at retail outlets three years after its initial rollout; it also continues to receive firmware updates. Much of the DIR-655's QoS technology was developed by a third party, Ubicom, and can also be found in selected routers manufactured by Netgear, Cisco, Trendnet, and others. If you're using another brand, the screens may look different, but the optimization options should basically be the same; you might just have to poke around to find them.
To get started, type the router's IP address into your browser of choice and hit Enter. The DIR-655's default IP address is 192.168.0.1, but I previously changed this router's address to 192.168.1.1 because the original address conflicted with my DSL modem.
(If you don't know your router's IP address, refer to its documentation. The most common router IP addresses are 192.168.1.1 for Linksys routers, 192.168.0.1 for D-Link and Netgear routers, 192.168.2.1 for Belkin routers and 192.168.11.1 for Buffalo routers. If you've changed the default IP address and don't remember what you changed it to, you might have to reset the router to its factory-default values.)
Type in your admin password to access the router's settings. If you've never created an admin password, now would be a good time.